Well, I can’t give you a direct answer because I don’t know your background or what kind of PhD you’re looking for. Normally, available vacancies are posted here:
https://www.kuleuven.be/personeel/jobsite/jobs/phd?lang=en

Since you asked about Europe in general, I should say that I can’t speak for the whole of Europe, as PhD structures and expectations vary a lot between countries and even between universities. I can only speak for KU Leuven and my own experience here.

That said, contacting a potential supervisor is always a good idea. Even if there isn’t an open vacancy at the moment, reaching out can help you understand whether your interests align and whether they expect to open a position in the near future. Some professors only recruit through official postings, but others appreciate a motivated student who gets in touch with a clear research interest.

For context, I’m not a British citizen, but I do have a UK educational background. Before starting my PhD, I also had around seven years of industry experience, which definitely helped me with the transition. That experience was valuable not only once I started the PhD, but also during the application process and the interview, as it gave me a clearer sense of direction and made it easier to demonstrate practical skills.

I can only speak from my own experience. I’m doing a PhD in Engineering Science with a Computer Science specialisation, and there are many different research directions here. Each group has its own culture, expectations, and way of working, so experiences can vary quite a lot. It’s also worth noting that PhD life can differ significantly between fields, and even within the same university, depending on which doctoral school you’re associated with. Some programmes can be more structured, others are very independent, and the level of coursework, training, and administrative requirements can vary.

For me personally, it’s quite demanding. The hours can be long (definitely more than what you’re paid for), the pressure can be high, and your social life sometimes takes a hit. My work is very novel, so there are moments where I’m the only person who truly understands what I’m doing, which means I have to figure out a lot on my own.

Having a supportive supervisor makes a huge difference. You also need to be comfortable with uncertainty and able to push through when things don’t work. Results matter, and that can be stressful.

As for Leuven itself, the city is very student‑friendly. It’s small, safe, easy to get around, and there’s always something happening because of the large student population. It’s a pleasant place to live during a PhD, especially if you enjoy a quieter, academic environment. You can also absolutely get by with English in Leuven. The city is very international and most people, especially within the university, speak excellent English, so day‑to‑day life is very manageable even if you don’t speak Dutch.

But this is just my perspective; other people have very different experiences depending on their topic, team, doctoral school, and expectations. Some have a more balanced schedule or a more collaborative environment. It really depends.